The Development Of Short-period Seismograph Acquisition Circuit

The short-period digital seismograph is one of the core measurement equipment commonly used in shallow seismic exploration and seismic monitoring systems,and it is widely used by the China Earthquake Administration for artificial seismic wide-angle catadioptric detection.In order to ensure that the seismograph obtains high-quality seismic data in the field artificial seismic exploration project,the instrument is required to have the characteristics of low power consumption,low time drift,miniaturization and integration,high precision and high dynamic range and high efficiency.At present,the domestic short-term seismograph independently developed has gradually become a mainstream device and is widely used,but there are still many functions and performance deficiencies in actual field exploration projects.Due to the late start,the technical level of development is limited,and domestic low power consumption,Large dynamic range,low time drift,wireless and convenient control and communication,lightweight integrated design and multi-function operation are simple seismic exploration instruments.With the increasing demand for instrument performance,functions,and field operations in current seismic monitoring and shallow seismic exploration,it is imperative to study a short-cycle digital seismograph with low power consumption,high accuracy,and multi-functional operation.The short-cycle seismograph designed in this paper is mainly composed of seismometer,acquisition circuit,casing structure and large-capacity battery.The seismometer is a short-cycle seismic sensor,and the acquisition circuit completes the acquisition and storage of the seismic signals output by the seismometer,and the large-capacity battery supplies power to all internal electronic components of the instrument.This paper focuses on the design methods and technical requirements of the seismograph,and aims at solving the current problems of low power consumption,high precision,low time drift and multi-function wireless control.Its main functions include acquisition and storage of seismic signals and pendulum offset state,calibration output of seismometer,GPS timing and punctuality,Android terminal interaction,etc.Focused on the research of large dynamic range,low power consumption,low time drift observation technology,according to the actual needs of chip selection survey,each module program setting,built by STM32,FPGA,ADC,GPS module,DAC,WIFI The hardware circuit composed of module,power circuit,magnetic control switch,SD card,LED,etc.has developed MCU control program and FPGA control program.At the end of this thesis,the indoor function test and performance test of short-cycle seismograph were carried out.In terms of function,continuous tests such as continuous acquisition,storage,timing,client interaction,power supply,and sensor calibration are carried out.Performance is mainly aimed at power consumption,dynamic range,range,noise,and time drift.Tests prove that the main functions of the software and hardware have all been verified,and in terms of performance,actual indoor testing shows that the power consumption during acquisition is less than 700mW,the dynamic range is up to 130dB@fs=50Hz,and the sampling rate is adjustable from 50 to 2000Hz,Acquisition range is 40VPP,clock stability is 0.15ppm.The above tests prove that the seismograph basically meets the expected design requirements,which lays the foundation for subsequent upgrades.